Your Sonos Ace went for an unintended swim, maybe a spill, a rainstorm, or a full drop into a puddle. Over-ear headphones have a different set of risks than earbuds, mostly because the cushioned ear cups act like sponges and trap moisture against the drivers and electronics.
The first and most important rule, do not press the power button. Do not plug in the USB-C cable. Do not try to connect via Bluetooth. Electricity flowing through wet circuits causes immediate shorts that turn a survivable situation into dead headphones in seconds. Set them down and start drying immediately.
For honest expectation-setting: Sonos does not market the Ace with any water resistance rating. The ear cups, headband, and internal components are not designed for submersion or heavy splashing. Survival is possible with fast action, but the steps below give them the best chance, not a guarantee.
Stop and Unplug Before Doing Anything
If the USB-C cable was plugged in when the headphones got wet, yank it out right now. If you had them powered on, leave them off. Don't try to turn them on to test, don't toggle ANC, don't open the Sonos app. Any electrical activity while water is inside the housing risks destroying the main board.
Pull the headphones off your head if you're wearing them wet. The accelerometer and head-detection sensor are on the PCB inside the housing, and moisture can wick through the ear cushion seam and reach them in minutes.
Get the Water Out of the Ear Cushions
Hold the headphones with the ear cups facing down and gently shake them to help water drain from the cushion foam and the mesh behind it. Don't swing them hard, you can stress the hinges and headband adjustment mechanism. A few gentle downward shakes are enough to dislodge visible droplets.
Pat the ear cushions firmly but not aggressively with a dry microfiber cloth. Focus on the outer leather-like surface and the inner foam area where your ear sits. If water is seeping from under the cushion edge, tilt the headphones to encourage gravity drainage for a few minutes before moving on.
Dry the USB-C Port Immediately
The USB-C port on the Sonos Ace is the most vulnerable opening on the whole headphone. Water pools here and can get drawn into the charging circuit. Use the corner of a lint-free cloth twisted into a point and gently wick moisture from inside the port. Do not jam anything metal in there. A few careful dabs, then hold the headphones so the port faces down and let gravity do the rest.
The button and capacitive touch surfaces on the ear cups also have tiny gaps. Blot the edges with the cloth, especially around the Power/Bluetooth button, which is where the factory reset action lives (hold it while plugging in USB-C). You do not want corrosion forming on that contact.
Air Dry for 48 Hours Minimum
Set the headphones on a dry, soft surface with the ear cups positioned so air can circulate around the cushions. Don't fold them flat, keep them in their natural open shape so moisture can escape from the headband padding and hinge areas. A windowsill with indirect airflow works well. Avoid direct sunlight, which can warp the plastic and degrade the battery.
Do not use a hair dryer, space heater, or radiator. Heat ruins the ear cushion foam, damages the battery cell, and can warp the headband. Do not bury them in rice, that's a persistent myth and it does nothing for internal moisture, plus rice dust can get into the USB-C port and the ear cup mesh. If you have silica gel packets, put them in a sealed container with the headphones for the drying period. That actually works.
Keep the headphones away from metal surfaces that could short the exposed USB-C pins. A wooden table or fabric surface is ideal.
Check for Signs of Corrosion Before Powering On
After 48 hours, inspect the USB-C port closely with a bright light. Look for greenish or whitish residue on the metal contact pins inside the port. Also check around the Power/Bluetooth button seams and the edge of the ear cushion where it meets the plastic housing. Corrosion anywhere is a bad sign.
If you see light residue on the USB-C port contacts, use a dry soft toothbrush to gently brush the pins. For stubborn corrosion, a cotton swab barely dampened with 90% or higher isopropyl alcohol can help, but only after you're certain the headphones are fully dry. The alcohol helps displace any lingering moisture.
Power On and Test in Stages
Plug the USB-C cable into a low-power source, like a computer port or a 5W charger. Watch the headphone behavior closely. If the LED indicator lights up normally within a few seconds, that's a good first sign. If you see flickering, smell anything unusual, or feel warmth from the ear cup housing, unplug immediately and let them dry another 24 hours.
After charging for 10 minutes, press and hold the Power/Bluetooth button to turn them on. Open the Sonos app on your phone and try to pair them. If they show up and connect, play a quick track to check the drivers. Test the microphone by recording a voice memo. Toggle ANC on and off to see if the noise cancellation works correctly, since water can damage the microphones that handle ANC.
Also test the capacitive touch controls on the ear cups, swipe for volume, tap for play/pause. If those are unresponsive, water may have gotten into the sensor layer. The head-detection sensor is worth testing too; put the headphones on and take them off to see if audio pauses and resumes.
USB-C audio mode requires firmware version 1.2 or later. If the headphones power on but don't work over the cable, check the Sonos app for a firmware update after they're connected. That's a post-damage step, not a fix for current issues, but worth knowing.
Even if everything works after drying, keep an eye on battery life over the next couple of weeks. Water damage sometimes shows up slowly as reduced playtime or random shutdowns. The Sonos app issues from the 2024 redesign can cause setup headaches, but that's separate from water damage, if the app won't find the headphones after drying, it's probably the app's fault, not the headphones'. Try reinstalling the app or using another device to confirm the headphones are still alive.